#!/usr/bin/env python
#################################################################################
# Copyright 2018 ROBOTIS CO., LTD.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, oftware
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#################################################################################

# Authors: Gilbert #

import rospy
from geometry_msgs.msg import Twist, Point, Quaternion
import tf
from math import radians, copysign, sqrt, pow, pi, atan2,cos,sin
from tf.transformations import euler_from_quaternion
import numpy as np
from sensor_msgs.msg import LaserScan

msg = """
control your Turtlebot3!
-----------------------
this is follower2
-----------------------
"""
tb_leader_pos=Point()
tb_follower1_pos=Point()
tb_follower2_pos=Point()
tb_leader_vel=Twist()
tb_follower2_vel=Twist()
obstacle_pos=Point()
K0=0.3
K1=0.1
K2=0.3
K3=0.1
detect_R=0.6
safe_r=0.2
ID=2
dx=-0.6
dy=-0.5


class GotoPoint():
    def __init__(self):
        rospy.init_node('follower2', anonymous=False)
        #turtlebot3_model = rospy.get_param("model")

        rospy.on_shutdown(self.shutdown)
        self.cmd_vel = rospy.Publisher('cmd_vel', Twist, queue_size=5)
        self.tb_follower2_positon=rospy.Publisher('/tb_follower2_pos',Point,queue_size=5)
        position = Point()
        move_cmd = Twist()
        r = rospy.Rate(10)
        self.tf_listener = tf.TransformListener()
        self.odom_frame = '/follower2/odom'
        try:
            self.tf_listener.waitForTransform(self.odom_frame, '/follower2/base_footprint', rospy.Time(), rospy.Duration(1.0))
            self.base_frame = '/follower2/base_footprint'
        except (tf.Exception, tf.ConnectivityException, tf.LookupException):
            try:
                self.tf_listener.waitForTransform(self.odom_frame, '/follower2/base_link', rospy.Time(), rospy.Duration(1.0))
                self.base_frame = '/follower2/base_link'
            except (tf.Exception, tf.ConnectivityException, tf.LookupException):
                rospy.loginfo("Cannot find transform between odom and base_link or base_footprint")
                rospy.signal_shutdown("tf Exception")
        print 66
        (position, rotation) = self.get_odom()
        rospy.Subscriber('/tb_leader_pos',Point,point_callback_1)
        rospy.Subscriber('/tb_follower1_pos',Point,point_callback_2)
        # rospy.Subscriber('/tb_follower2_pos',Point,point_callback_3)
        rospy.Subscriber('/tb_leader_vel',Twist,vel_callback_4)
        self.tb_follower2_positon.publish(position)

        global tb_leader_vel
        global tb_follower1_pos
        global tb_follower2_pos
        global tb_follower2_vel
        global obstacle_pos
        delta_x=(tb_leader_pos.x-position.x+dx)
        delta_y=(tb_leader_pos.y-position.y+dy)
        # print ('deltax of Node 2 is %f'%(delta_x))

        avoid_delta=0

        tb_follower2_pos=position
        obstacle_pos=self.lidar(position)
        # print ('follower 2 obstacle x=%f y=%f'%(obstacle_pos.x,obstacle_pos.y))
        # theta=self.compute_theta(tb_leader_pos.z,rotation)
        r=sqrt(pow(obstacle_pos.x-position.x,2)+pow(obstacle_pos.y-position.y,2))
        print ('follower 2 obstacle d=%f ang=%f'%(r,obstacle_pos.z))
        if r<detect_R and (obstacle_pos.z<70 or obstacle_pos.z>290):
            theta2=self.compute_theta(obstacle_pos.z,0)
            if(obstacle_pos.z<70):
                tb_follower2_vel.angular.z=-0.4*(pi/4-theta2)-0.1
                tb_follower2_vel.linear.x=0.2/(r+0.3)
            else:
                tb_follower2_vel.angular.z=0.4*(pi/4+theta2)+0.1
                tb_follower2_vel.linear.x=0.2/(r+0.3)
            #tb_follower2_vel.angular.z=tb_follower2_vel.angular.z*(-1);
            self.cmd_vel.publish(tb_follower2_vel)

        else:
            theta=tb_leader_pos.z-rotation
            tb_follower2_vel.linear.x=K0*tb_leader_vel.linear.x*cos(theta)+K1*delta_x
            print ('follower 2 velecity=%f'%(tb_follower2_vel.linear.x))
            tb_follower2_vel.angular.z=K0*tb_leader_vel.angular.z+K2*theta+1.3*tb_leader_vel.linear.x*delta_y*(sin(theta)/theta)
            self.cmd_vel.publish(tb_follower2_vel) 

    def lidar(self,tb_pos):
        msg = rospy.wait_for_message("scan", LaserScan)
        LIDAR_ERR = 0.05
        LIDAR_MAX = 2
        obstacle=[]
        min_dis=3
        min_ang=0
        min_point=Point()
        for i in range(360):
            if i <= 90 or i > 270:
                obstacle_pos=Point()
                if msg.ranges[i] >= LIDAR_ERR and msg.ranges[i]<=LIDAR_MAX:
                    obstacle_pos.x=tb_pos.x+msg.ranges[i]*cos(i*2*pi/360)
                    obstacle_pos.y=tb_pos.y+msg.ranges[i]*sin(i*2*pi/360)
                    obstacle.append(obstacle_pos)
                    if msg.ranges[i] < min_dis:
                            min_dis = msg.ranges[i]
                            min_ang = i
        if min_dis<3:
            min_point.x=tb_pos.x+min_dis*cos(i*2*pi/360)
            min_point.y=tb_pos.y+min_dis*sin(i*2*pi/360)
            min_point.z=min_ang
        else:
            min_point.x=-1000
            min_point.y=-1000
        return min_point


    def compute_theta(self,theta,rotation1):
        # if theta*rotation1<0:
        #     if theta>0:
        #         if abs(rotation1)+theta<=pi:
        #             w=abs(rotation1)+theta
        #         else:
        #             w=-(2*pi+rotation1-theta)
        #     else:
        #         if rotation1+abs(theta)<=pi:
        #             w=-(abs(theta)+rotation1)
        #         else:
        #             w=(2*pi-rotation1+theta)
        # else:
        #     w=theta-rotation1

        theta=theta%(2*pi)
        if theta>pi:
            theta=theta-2*pi
        rotation1=rotation1%(2*pi)
        if rotation1>pi:
            rotation1=rotation1-2*pi
        w=theta-rotation1
        return w
        


    def get_odom(self):
        try:
            (trans, rot) = self.tf_listener.lookupTransform(self.odom_frame, self.base_frame, rospy.Time(0))
            rotation = euler_from_quaternion(rot)

        except (tf.Exception, tf.ConnectivityException, tf.LookupException):
            rospy.loginfo("TF Exception")
            return

        return (Point(*trans), rotation[2])
    def shutdown(self):
        self.cmd_vel.publish(Twist())
        rospy.sleep(1)
   
        

def point_callback_1(data):
    global tb_leader_pos
    tb_leader_pos.x=data.x
    tb_leader_pos.y=data.y
    tb_leader_pos.z=data.z
def point_callback_2(data):
    global tb_follower1_pos
    tb_follower1_pos.x=data.x
    tb_follower1_pos.y=data.y
def point_callback_3(data):
    global tb_follower2_pos
    tb_follower2_pos.x=data.x
    tb_follower2_pos.y=data.y
def vel_callback_4(data):
    global tb_leader_vel
    tb_leader_vel=data





if __name__ == '__main__':
    try:
        timer=0
        while not rospy.is_shutdown():
            print(msg)
            GotoPoint()
            # timer=timer+1
            # print ('follower2 timer= %d'%(timer))

    except:
        rospy.loginfo("shutdown program.")

